I always wanted to own an AGP2PCI or AGP5 adapter and play with it, but no way I could ever afford to pay 100+ Euro on one. Solution? Build one myself.
Step one: construction of the adapter:
Connecting signals, power and ground.
Adding insulating wrapping.
Adding metal foil shielding connected to ground.
Step 2: Modding motherboards BIOS for compatibility:
]
The adapter allows using AGP 3.3v cards plugged into PCI-X slot. The only motherboard with 3.3v PCI slots I have is Tyan S2466 that is known for being incompatible with AGP2PCI type adapters, so a BIOS hack was performed.
Function is 100% stable. There is a small performance drop as expected, for example tested with a 128Mb Voodoo5 AGP, 2326 3DMark2001SE points versus 2645 when tested into AGP slot, but more than acceptable due to bus sharing.
I know, it's ugly, but it works, it's cheap and easy to build.